astakos: Update message to reflect newer option

* Update message shown after service registration
* Add a license to the file
docs: Update install guides
common: Fix type error issue

Fix TypError issue cause by an unknown 'timeout' argument to
'get_confirms' call.
Update Changelog
pithos: Move storage sync script to Pithos tools
Add upgrade notes for version 0.15.1
Update NEWS file for v0.15.1

Also fix some typos in the Upgrade guide.